In the fast food industry, developing an ideal package for sandwiches, french fries, and the like, poses special problems. It is desirable to protect the product, but the package must be inexpensive. The package should occupy as little room as possible when shipped and stored awaiting use. It should be easy to use without much training or skill, and not awkward to close about the product. In many situations it is very advantageous if the package can be used as a surface on which to assemble a product such as a sandwich. The package should retain heat, but allow some venting of moisture to prevent sogginess of buns or french fries.
Conventional package designs for the fast food industry usually provide only one or two of the desirable features listed above. Simple wax paper wrapping sheets for sandwiches, for instance, provide an assembly surface and retain heat to some extent, but also retain moisture. They provide almost no protection against crushing the product.
Molded foam or paperboard boxes for sandwiches are relatively expensive because they enclose the entire article in rigid material, and they take up considerable space in the restaurant while awaiting use. Although paperboard boxes may be shipped flat, significant effort and time must be expended to pre-assemble the boxes prior to use. Boxes, furthermore, do not provide convenient surfaces for assembling sandwiches. An extra motion is therefore required to load the sandwich into the box. A lock of some sort is usually provided, and may be awkward to engage, or subject to breaking apart.
Open top french fry containers or bags provide considerable ventilation, but do not retain heat to keep the food warm between cooking and consumption.
Some attempts have been made to combine flexible wrapping materials, which have cost and space-saving characteristics, with paperboard sleeves to help protect sandwiches. These attempts have been less than successful. U.S. Pat. No. 3,964,669 discloses a central rigid member which is folded to surround the sandwich with a rigid sleeve and provide a paperboard handle. An outer flexible sheet attached to the rigid member extends beyond the open ends of the sleeve and must be tucked in or twisted to close the package in an unstable, unreliable fashion. Furthermore, awkward panels formed in the paperboard must be lifted and held back in order to place the sandwich in its proper position. U.S. Pat. No. 4,575,000 discloses an inner layer of glassine type paper and an outer layer of paperboard, again forming a rigid sleeve around the sandwich being wrapped. The extending glassine paper ends of the sleeve must be tucked under the sandwich, so that no positively fastened closure is provided. In the case of both of these patented packages, the flexible layer is provided flat and without preforming to assist the user in forming and closing the package. The tucking required to complete the package may result in crushing the contents. Furthermore, the principle is followed that the paperboard portion must surround the sandwich and form the top closure over the sandwich. Other lined containers are disclosed in U.S. Pat. Nos. 1,704,175; 2,011,179; 2,556,321 and 3,627,541.
Thus, a need exists in the art for a package for food having the desirable features listed above, which uses a small amount of paperboard efficiently to protect the food, which in effect guides the user in assembling the package, and which provides a positive closure and handle without complex paperboard structures.